KR940009945B1 - Chemical vapor growth apparatus - Google Patents

Abstract

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Description

Chemical vapor growth apparatus

1 is a cross-sectional configuration diagram showing a chemical vapor growth apparatus according to a first embodiment of the present invention,

2 is an explanatory diagram showing the state of flow in the reaction chamber of the chemical vapor growth apparatus according to Example 1 of the present invention.

3 is an explanatory diagram showing a gas head according to the first embodiment of the present invention.

4 is a bird's eye view showing the distribution of the thickness of the reaction product film formed by the gas head of FIG.

5 is an explanatory diagram showing another gas head according to the first embodiment of the present invention.

6 is a bird's eye view showing the distribution of the thickness of the reaction product film formed by the gas head of FIG.

7 is a bird's eye view showing the distribution of the thickness of another reaction product film formed by the gas head of FIG.

8 is a bird's eye view showing the distribution of the thickness of another reaction product film formed by the gas head of FIG.

9 is a cross-sectional view showing a chemical vapor growth apparatus according to a second embodiment of the present invention.

10 is a schematic block diagram showing a chemical vapor growth apparatus according to a third embodiment of the present invention.

11 is a schematic block diagram showing a chemical vapor growth apparatus according to a fourth embodiment of the present invention.

12 is a cross-sectional configuration and plan view showing a chemical vapor growth apparatus according to a fifth embodiment of the present invention.

13 is a cross-sectional view showing a conventional chemical vapor growth apparatus.

14 is a block diagram showing a conventional continuous chemical vapor growth apparatus.

15 is a cross-sectional view showing the film forming reaction portion of the conventional continuous chemical vapor growth apparatus.

* Explanation of symbols for main parts of the drawings

1: semiconductor wafer 2: stage

3: heater 4: reaction chamber

5: gas head 6a: N ₂ gas outlet

6b: reaction gas outlet 6c: N ₂ gas outlet

B: reaction gas C: N ₂ gas.

17: The membrane 17a: The membrane

17b: partition 6a: N ₂ gas outlet

6b: reaction gas outlet 6c: N ₂ gas outlet

B: reaction gas C: N ₂ gas.

The present invention relates to a chemical vapor growth apparatus suitable for use in forming a thin film on a semiconductor wafer as a workpiece.

As a conventional chemical vapor growth apparatus of this kind, there is one known from Japanese Patent Laid-Open No. 2-283696. FIG. 13 is a cross-sectional configuration diagram showing such a conventional chemical vapor growth apparatus, in which FIG. 2 is a heating stage holding semiconductor wafer 1 on which a reaction generation film (not shown) is formed, and 3 is this stage ( A heater for heating 2), a reaction chamber for processing a semiconductor wafer 1 in which a thin film is formed by a reaction gas in a sheet, and 5, a stage 2 is provided at intervals, and the reaction gas B A gas head having a plurality of gas outlets 6 for supplying, 7 is a reaction chamber side wall surrounding the reaction chamber 4, 8 is an exhaust ring, 9 is an exhaust chamber, 10 is installed in the reaction chamber wall 7, and exhausted. An exhaust port for deriving A, an exhaust outlet port, 11 an exhaust flange, 13 an exhaust resistance plate, and 14 an exhaust port for preventing the heat of the stage 2 from escaping to the outside by conduction, and for rotating the stage. It's a stage gap. 15 is the N ₂ spout, and 16 is the N ₂ spout ring.

In the conventional chemical vapor growth apparatus configured as described above, reaction reaction is generated on the semiconductor wafer by supplying the reaction gas B ejected from the gas ejection opening 6 to the semiconductor wafer 1 previously heated on the stage 2. A film can be formed.

Since the conventional chemical vapor growth apparatus is configured as described above, since the growth rate of the reaction generation film depends on the gas concentration supplied from the gas head 5 to the semiconductor wafer 1, the thickness of the reaction generation film is made uniform. In order to stabilize and uniformize the concentration of the reaction gas B at any site on the semiconductor wafer 1, it was necessary to make the flow of the reaction gas B stable and uniform.

In addition, the reaction gas (B) generates a reaction product (D) due to the gas phase reaction, which adheres to each part of the inner wall of the reaction chamber, then peels off from the inner wall and adheres to the semiconductor wafer (1), thereby reducing the yield of the product. It was the cause.

Alternatively, in order to avoid a decrease in yield, the reaction chamber needs to be frequently cleaned to remove the reaction product (D), and there is a problem that productivity is lowered. Therefore, it was necessary to reduce the generation of the reaction product D and to send it out from the reaction chamber 4 together with the exhaust A.

The present invention has been invented to solve the above problems, and it is possible to control the flow and composition of the reaction gas in the reaction chamber, so that a reaction product film having a uniform film thickness can be obtained, and moreover, foreign matter into the reaction chamber. It is an object of the present invention to provide a chemical vapor growth apparatus that can reduce the adhesion of.

In the chemical vapor growth apparatus according to the present invention, the gas head for supplying the reaction gas is multiplied to supply the reaction gas from the center portion, and the inert gas is supplied at the end at the same blowing rate.

In the chemical vapor growth apparatus of the present invention, since the reaction gas at the end of the gas head can be replaced with an inert gas, a uniform film can be formed without disturbing the flow in the reaction chamber.

In addition, since unnecessary reaction at a point far from the wafer surface is suppressed, generation of foreign matter adhering to the reaction chamber inner wall can be reduced.

EXAMPLE 1

Hereinafter, the present invention will be described in detail with reference to the embodiments shown in the drawings.

FIG. 1 is a block diagram showing a chemical vapor growth apparatus according to an embodiment of the present invention, and FIG. 2 is an explanatory view showing a flow in a reaction chamber of the chemical vapor growth apparatus according to an embodiment of the present invention.

In the drawings, the same members as those in the thirteenth drawing are denoted by the same reference numerals and description thereof will be omitted.

FIG. 1, according to claim 13 also, 6a and 6b are a N ₂ gas (B) containing TEOS and O ₃ is placed a partition (17), respectively, N ₂ gas (inert gas) (C) and a reactive gas It is a gas outlet which blows out. Since the gas is ejected at a uniform and the same velocity, the flow velocity distribution in the reaction chamber is the same as that of the reaction chamber using a conventional gas head having a single ejection opening, as shown in FIG. An over temperature boundary layer is formed.

In the figure, E denotes the boundary line of the reaction gas concentration, F denotes the boundary line of the temperature distribution, and H denotes an unnecessary reaction occurrence region. The temperature boundary line F indicating the boundary of the temperature required for the reaction of the TEOS-O ₃ mixer to become active is present in almost parallel to the stage surface.

On the other hand, the TEOS-O ₃ concentration near the wafer surface is the same as in the case of single ejection, with the radius of the partition 17 being controlled and not affected by the surrounding N ₂ .

However, since the dilution by the ambient N ₂ in the position apart from the wafer surface, TEOS-O ₃ concentration is reduced. At this time, the temperature at the periphery is high enough for TEOS-O ₃ to react, but because the concentration of TEOS-O ₃ is low, a region (H) where reaction products do not occur is generated.

In the case of the conventional single ejection, this area is an area where unnecessary reactions occur that do not contribute to the film formation of the wafer 1, and according to the present invention, the production amount of the reaction product D adhering to the reaction chamber inner wall can be reduced.

Here, the size of the portion supplying the reaction gas B at the center of the gas head 5, the portion supplying the N ₂ gas C at the outer circumference, and the thickness distribution of the film formed on the semiconductor wafer 1 The explanation is based on actual data.

3 shows a circular gas head 5 having a diameter of the reaction gas supply portion 110 mm in the center portion and a total outer diameter of 150 mm, a semiconductor wafer 1 facing each other at a distance of 7 mm, and a stage 2. 4 is an explanatory view showing the thickness distribution of the reaction product film formed on the semiconductor wafer 1 when the film is formed in the state shown in FIG.

Similarly, FIG. 5 shows a circular gas head 5 having a diameter of the reaction gas supply portion of the central portion of 90 mm and an overall outer diameter of 150 mm, and a semiconductor wafer 1 and a stage 2 facing each other at a distance of 7 mm. FIG. 6 is an explanatory view showing the thickness distribution of the reaction product film formed on the semiconductor wafer 1 when the film is formed in the state shown in FIG.

In FIG. 4, in FIG. 3, the film was formed with the average flow velocity on the gas head 5 of the reaction gas B and the average flow velocity on the gas head 5 of the N ₂ gas C being the same (about 26 mm / sec). This is a bird's eye view showing the thickness distribution of the reaction generation film formed on the semiconductor wafer 1 at this time. It can be seen that (B) has reached the entire surface of the semiconductor wafer 1.

FIG. 6 is a film in which the average flow velocity on the gas head 5 of the reaction gas B and the average flow rate on the gas head 5 of the N ₂ gas C are the same (about 26 mm / sec) in FIG. Is a bird's eye view showing the distribution of the thickness of the reaction product film formed on the semiconductor wafer 1 in accordance with this. According to this, the thickness of the film is reduced in the outer peripheral portion compared to the center portion on the semiconductor wafer 1, Since the reaction gas B supplied from the central portion does not reach the entire surface of the semiconductor wafer 1, and the N ₂ gas C from the gas head outer peripheral portion reaches the outer peripheral portion of the semiconductor wafer 1 by diffusion, the thickness of the film is increased. You can see that it became thin.

From the above results, when the distance between the gas head 5 and the semiconductor wafer 1 is 7 mm and the outer diameter of the gas head 5 is 150 mm, the size of the reaction gas supply portion at the center of the gas head 5 is 110 mm. Up to), the supplied reaction gas (b) reaches the entire surface on the semiconductor wafer 1 and a reaction generation film having a uniform thickness is formed, but at a size smaller than that, the reaction gas supplied from the reaction gas supply portion in the center of the gas head (5) Since (b) does not reach the entire surface of the semiconductor wafer 1, the thickness of the film decreases at the periphery of the semiconductor wafer 1.

Therefore, in the above-described distance between the gas head 5 and the semiconductor wafer 1 and the outer diameter of the gas head, the size of the reaction gas supply portion at the center of the gas head 5 can be reduced to a diameter of 110 mm, and according to the area thereof. As a result, it is possible to reduce the reaction gas B that does not contribute to the film formation, which has been exhausted without reaching the semiconductor wafer 1.

However, the minimum size that can be formed uniformly on the semiconductor wafer 1 of the reaction gas supply portion in the center of the gas head 5 is the outer diameter of the gas head 5 and the semiconductor wafer 1 between the outer diameter of the gas head and the gas. It is determined by the supply amount, and is not limited to the above value.

Next, the average flow velocity on the gas head 5 of the reaction gas B from the reaction gas supply part in the center of the gas head 5, and the gas head 5 of the N ₂ gas C from the outer peripheral part of the gas head 5. The distribution of the average flow velocity of the? Phase and the thickness of the reaction product film formed on the semiconductor wafer 1 will be described based on the actual data.

4, 7 and 8 are the bird's-eye view which shows the thickness distribution of the reaction production | generation film formed on the semiconductor wafer 1, when the film | membrane was formed by changing the gas flow velocity in the structure of FIG.

4, when the film formation is performed with the ratio of the average flow velocity on the gas head 5 of the reaction gas B and the average flow velocity on the gas head 5 of the N ₂ gas C as 1: 1. According to this, according to this, the film thickness of the center part on the semiconductor wafer 1 and the film thickness of the outer peripheral part are equal.

In FIG. 7, in FIG. 3, the film was formed with a ratio of the average flow rate of the gas head 5 of the reaction gas B and the average flow rate of the N ₂ gas C on the gas head 5 as 1: 0.77. With the thickness distribution at the time, according to this, the thickness of the outer peripheral part becomes thinner with respect to the film thickness of the center part on the semiconductor wafer 1. This is because the flow rate of the N ₂ gas C supplied from the outer circumferential portion of the gas head 5 is smaller than the flow rate of the reaction gas B supplied from the center of the gas head 5, so that the reaction gas B and the N ₂ gas are present. This is because the boundary of (C) is weakly pushed up to the semiconductor wafer 1 by the flow of the N ₂ gas C, so that the concentration of the reaction gas B becomes thin at the outer circumferential portion on the semiconductor wafer 1.

In FIG. 8, in FIG. 3, the film was formed with a ratio of the average flow rate on the gas head 5 of the reaction gas B and the average flow rate on the gas head 5 of the N ₂ gas C as 1: 1.19. With the thickness distribution at the time, according to this, the thickness of the outer peripheral part becomes thick with respect to the thickness of the center part on the semiconductor wafer 1. This is because the flow rate of the N ₂ gas C supplied from the outer circumferential portion of the gas head 5 is larger than the flow rate of the reaction gas B supplied from the center of the gas head 5, so that the reaction gas B and the N ₂ gas are present. This is because the force of the boundary of (C) being pushed up to the semiconductor wafer 1 by the flow of the N ₂ gas (C) becomes strong, so that the concentration of the reaction gas (B) increases in the outer peripheral portion on the semiconductor wafer (1). .

From the above results N ₂ gas supplied from the gas head 5 of the outer N ₂ gas supply unit for average flow rate on the reaction gas (B) the gas head 5 of which is supplied from the reaction gas supply part of the central portion the gas head 5 By changing the average flow velocity on the gas head 5 in (C), the thickness of the outer peripheral portion of the reaction product film formed on the semiconductor wafer 1 can be changed with respect to the thickness of the central portion.

Therefore, when the nonuniformity in the circumferential direction occurs in the thickness of the reaction product film formed on the semiconductor wafer 1 due to some factor, the flow rate of the N ₂ gas C supplied from the N ₂ gas supply part of the outer circumference of the gas head 5 is caused. The thickness distribution of the reaction product film formed on the semiconductor wafer 1 can be made uniform by changing the thickness in the direction in which the thickness unevenness is eliminated by changing the.

EXAMPLE 2

9 is a cross-sectional configuration diagram showing a chemical vapor growth apparatus according to a second embodiment of the present invention. In the drawings, the same members as those in FIG. 1 are denoted by the same reference numerals, and description thereof is omitted.

In figure 6a and 6b is N ₂ gas jet port, 6b for ejecting N ₂ gas is a reaction gas outlet for ejecting N ₂ gas containing a reaction gas of TEOS and O _3.

The jets 6a and 6b and the jets 6a and 6c are partitioned into partitions 17a and 17b, and the N ₂ gas jets 6a and the reactive gas jets 6b are uniform and at the same speed. is ejected, N ₂ gas jet port (6c) are from the N ₂ gas is ejected at a faster rate than the other outlet.

For example, in a gas head having an outer diameter of 150 mm, the diaphragm 17a is set to a diameter of 90 mm, the diaphragm 17b is set to a diameter of 120 mm, and the flow rate of the gas is set to 6a: 6b: 6c = 1: 1: 1.2. . At this time, if the ejection flow rate ratio is 6a: 6b: 6c = 1: 1: 1, as shown in FIG. 6, the thickness of the film at the periphery of the semiconductor wafer 1 decreases, but the flow rate of the ejection opening 6c is high. The film thickness is canceled by the effect of increasing the thickness of the film due to the rapid jet flow rate shown in FIG. 8, so that uniform thickness distribution can be realized.

As a result, the required supply amount of the reaction gas is further reduced, and the reaction in the gaseous phase which is unnecessary can also be suppressed.

EXAMPLE 3

FIG. 10 is a schematic configuration diagram showing a chemical vapor growth apparatus according to a third embodiment of the present invention. In the drawings, the same members as those in FIG. 1 are denoted by the same reference numerals and description thereof will be omitted.

In figure 6a is N ₂ gas jet port, 6b and 6d for ejecting N ₂ gas is a jet port for ejecting N ₂ gas containing a reaction gas of TEOS and O _3. The ejection openings 6a and 6b, the ejection openings 6a and 6d are divided into partitions 17a and 17c, and the reaction gas ejected from the reaction gas ejection openings 6b and 6d is a mass controller 19a. The composition is adjusted by (b), (19b), (19c), and the magnitude | size of each ejection speed is adjusted by valve | bulb 18a (18b). The N ₂ gas ejection rate ejected from the N ₂ gas ejection port 6a is controlled by the mass flow controller 19d.

Since it is comprised in this way, the thickness distribution of the center part of the semiconductor wafer 1 can be arbitrarily controlled by the effect of the thickness change by the ejection flow velocity shown to FIG. 7, FIG. Can be realized.

In addition, although the valves 18a and 18b were used to change the flow rate ratio of the reaction gas ejection openings 6b and 6d here, it is not limited to this, but for example, a tubing having a large flow resistance is provided. The flow rate ratio can be changed by adjusting the length. Alternatively, two sets of massflow controllers can be used to control the flow rate ratio.

EXAMPLE 4

11 is a schematic configuration diagram showing a chemical vapor growth apparatus according to a fourth embodiment of the present invention. In the drawings, the same members as those in FIG. 1 are denoted by the same reference numerals, and description thereof is omitted.

In the figure, 19e is a mass flow controller for quantitatively adding isobutene (C ₄ H ₈ ), which is a reaction inhibiting gas, to the N ₂ gas stream (C) of the outer circumference.

Since isobutene (C ₄ H ₈ ) has a high reactivity with O atoms generated by pyrolysis of O _3, the reaction of O atoms with TEOS can be prevented. Isobutene (C ₄ H ₈ ) contained in the N ₂ gas stream C in the periphery occurs at a distance from the substrate and reacts with TEOS to capture O atoms that generate precursors of the powder. The occurrence is reduced.

Here, although isobutene (C ₄ H ₈ ) was used as the reaction inhibiting gas, the same effect is expected as long as it is a chemical species capable of effectively trapping O atoms. Examples thereof include hydrocarbons such as C ₂ H ₄ and C ₃ H ₆ , and alcohols such as methanol and ethanol.

EXAMPLE 5

The above has been described using a concentric film forming apparatus, but the case where the present invention is used in a continuous chemical vapor growth apparatus will be described next.

FIG. 14 is a block diagram showing a conventional continuous chemical vapor growth apparatus, and FIG. 15 is a cross-sectional block diagram showing a film forming reaction part of the device.

In the drawings, 1 is a semiconductor wafer on which a reaction generation film (not shown) is formed, 2 is a stage for holding and conveying the semiconductor wafer 1, 3 is a stage 2, and a semiconductor wafer loaded thereon ( The heater for heating 1) to a predetermined temperature, 5, in order to uniformly supply the reaction gas B to the semiconductor wafer 1, a plurality of slits are provided on the entire surface of the surface facing the semiconductor wafer 1 The gas head 20 which is comprised is provided as if covering the some gas head 5, and is an exhaust cover for removing the exhaust A. As shown in FIG.

Since the conventional continuous chemical vapor growth apparatus is configured as described above, the reaction gas B supplied from the end of the gas head 5 toward the semiconductor wafer 1 does not reach the semiconductor wafer 1. Flow as exhaust (A). Here, the reaction gas (B) generates a reaction product (D) by an imaginary reaction, and the reaction product (D) is attached to the exhaust cover (20) by the gas head (5), and then falls off to the semiconductor wafer (1). Since it adhered to a phase, it was a cause of the yield fall of a product. In addition, the device was set up regularly to remove the reaction product (D), which caused a decrease in the operation rate of the device.

12A and 12B are cross-sectional views and plan views respectively showing a continuous chemical vapor growth apparatus according to a fifth embodiment of the present invention. The gas head 5 has a front face slitting of the surface facing the semiconductor wafer 1 as in the prior art, but the reaction gas B is supplied only from the center of the slitting, and the gas head 5 closes to the exhaust A. From the slits at both ends, N ₂ gas (C) is supplied at the same flow rate as the reaction gas (B).

At this time, the reaction gas B supplied from the center part of the gas head 5 reaches only the semiconductor wafer 1, and performs a film-forming reaction. The N ₂ gas C to be supplied from both ends of the gas head 5 is exhausted without reaching the semiconductor wafer 1 without disturbing the flow of the reaction gas B at the same flow rate as the reaction gas B. .

As described above, according to the present invention, since the reaction gas B supplied from the gas head 5 and exhausted without reaching the semiconductor wafer 1 is replaced with an inert N ₂ gas C, the reaction gas B It is possible to improve the yield of the product, the operation rate of the device, and the like without the reaction product (D) generated by the gas phase reaction of being attached to the gas head 5 or the exhaust cover 20.

In addition, since the required supply amount of the reaction gas decreases with the area of the slits to which the reaction gas is supplied, the reaction gas to be used can be saved.

The shape arrangement of the stage, the heater, the gas head, the exhaust cover, and the like of the continuous chemical vapor growth apparatus described above is not limited thereto, and the gas supplied from both ends of the gas head is also inert gas that does not participate in film formation instead of N ₂ gas. You can also use

In addition, this time, some have described TEOS-O ₃ as an example, but it is also true that it can be applied to the case of using a reaction gas that is oscillated by gas phase reaction. Moreover, the same effect can be expected even if it flows other inert gas instead of N <_{2> in an} outer peripheral part.

As described above, according to the present invention, the gas head is separated into a reaction gas outlet at the center and an inert gas outlet at the end, and the flow rates of the gases ejected from the reaction gas outlet and the inert gas outlet adjacent to the gas outlet are the same. Since it is possible to form a film with a small amount of reaction gas while maintaining a uniform film thickness.

In addition, adhesion of foreign matter to the reaction chamber can be reduced.

Claims (1)

A reaction chamber for processing a semiconductor wafer on which a thin film is formed by a reaction gas for each sheet, a gas head for supplying the reaction gas to the semiconductor wafer provided to face the periphery of the semiconductor wafer placed in the reaction chamber, and the semiconductor wafer. In the chemical vapor growth apparatus comprising a stage for heating, the gas head is separated into a reaction gas outlet at the center and an inert gas outlet at the end, and is ejected from the reaction gas outlet and the inert gas outlet adjacent to the gas outlet. Chemical vapor growth apparatus characterized in that the flow rate of each gas to be the same.